I. Field of the Invention
The present invention relates to an improved suspension system for vehicles, such as snowmobiles, that derive their support from an endless belt or track supported on a resilient biased suspension system including bogie-wheel suspension assemblies and, in particular, the present invention relates to a means for providing lubrication for such bogie-wheel suspension assemblies.
II. Description of the Prior Art
As is well known in the art of suspension systems means must be provided for applying the weight of a track snow vehicle upon the ground engaging portion of the track in as uniform a manner as possible. To effect this end, wheel bogies have been used which carry one or more relatively small wheels or alternately skids, that contact the upper surface of the ground-engaging portion of the track. Such systems, when properly designed, afford good traction and do not necessitate the use of an objectionally heavy suspension component. Examples of such systems are disclosed in U.S. Pat. No. 3,761,144. In this system a bogie-wheel suspension assembly is provided for the resiliently biased rolling support of an endless track on a vehicle chassis. The system comprises a trailing frame assembly adapted at its upper part for pivotal attachment to the vehicle chassis by means of a tubular sleeve through which a bearing shaft is inserted for connection to the vehicle chassis. A lower part of the trailing frame is pivotally connected to a wheel support member having at least two wheels mounted for rotation thereon behind the other in a longitudinal direction of the chassis. The trailing frame has a spring connection with the chassis for resiliently urging the frame and the wheels downwardly and forwardly with respect to the vehicle against the inner surface of the track to provide a support for the endless track of the snowmobile. This arrangement has been necessary to provide lubrication between the interface of the outer surface of the shaft and the inner surface of the tubular sleeve. In order to achieve this, it has been necessary to disconnect the entire bogie-wheel suspension assembly from the chassis and remove the same such that the shaft may be removed from the tubular sleeve and grease or other suitable lubricant inserted therein between the sleeve and the shaft. In some applications it is not uncommon to use as many as 12 to 16 bogie-wheels which necessitate a considerable effort in order to remove the bogie-wheel suspension assembly in order to provide for proper lubrication. Because of the extensive amount of work necessary to lubricate the bogie-wheel shaft, it is not uncommon for owners of such snowmobiles to bypass this necessary operation. As a result, the bogie-wheel shaft tends to wear out prematurely necessitating the expensive replacement of the same.